Final answer:
For a cable modem, the upstream communications are typically in the lower frequency range, while downstream communications are in the higher frequency range to minimize noise and signal degradation.
Step-by-step explanation:
In cable modem technology, the typical sub-band return frequency design features upstream communication in the lower frequency range and downstream communication in the higher frequency range.
The lower end of the frequency spectrum, which includes long wavelengths and low energy, is where you tend to find AM radio signals. In contrast, FM signals, with their constant amplitude and varying instantaneous frequency, operate at higher frequencies. For cable modems, using the lower frequency spectrum for upstream communication helps to minimize noise and signal degradation over the network.
Therefore, the answer to the student's question is A) Upstream in the lower frequency range.